1. Technical Field
The present invention relates to a semiconductor memory apparatus, and more particularly, to a sense amplifier control signal generating circuit of a semiconductor memory apparatus.
2. Related Art
Semiconductor memory apparatuses may include memory cells having capacitors, bit lines for transmitting data of the memory cells, and a sense amplifier for sensing the data transmitted through the bit lines.
The capacitor stores a low or high potential according to the data transmitted through the bit lines, and information stored in the capacitor is transmitted to the sense amplifier through the bit lines. Then, the sense amplifier amplifies the transmitted information.
For example, when high-level information is stored in the capacitor, the high-level information stored in the capacitor is transmitted to the sense amplifier through a pair of bit lines including of a bit line and a bit line bar. When no data is transmitted, the bit line and the bit line bar are always pre-charged with a bit line pre-charge voltage VBLP. Therefore, the high-level information output from the capacitor is applied to the bit line, and the bit line bar is maintained at the bit line pre-charge voltage VBLP.
The sense amplifier amplifies a potential difference between the bit line and the bit line bar. The potential difference between the bit line and the bit line bar should be higher than a predetermined level so as to perform a sensing operation of the sense amplifier.
The sense amplifier starts the sensing operation when a predetermined amount of time has elapsed after data is transmitted through the bit line. The sense amplifier performs the sensing operation in response to a sense amplifier control signal for driving the sense amplifier.
As shown in FIG. 1, a sense amplifier control signal generation circuit according to the related art may include a delay unit 10 that delays an active signal ACT and a sense amplifier control signal generating unit 20 that generates a sense amplifier control signal Senamp_ctrl for driving the sense amplifier in response to an output signal of the delay unit 10. The sense amplifier control signal Senamp_ctrl includes a pull-up signal and a pull-down signal.
Such a conventional sense amplifier is driven after elapse of the delay time when the sense amplifier control signal Senamp_ctrl is generated.
However, the sense amplifier is not operated immediately after a potential difference for allowing the sense amplifier to perform a normal sensing operation due to the delay unit. Therefore, a time tRCD required to start a reading or writing operation after an active command is received is increased. As a result, a response speed the semiconductor memory apparatus is lowered.